.tr {
background-position:right top;
right:0px;
top:0px;
}

.tl {
background-position:left top;
left:0px;
top:0px;
}

.br {
background-position:right bottom;
bottom:0px;
right:0px;
}

.bl {
background-position:left bottom;
bottom:0px;
left:0px;
}

.tl, .tr, .bl, .br {
	display:block;
	font-size:0pt;
	height:5px;
	position:absolute;
	width:5px;
}